U.S. patent application number 16/477714 was filed with the patent office on 2019-11-28 for method for joining dissimilar materials, and dissimilar-material joined body.
This patent application is currently assigned to KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.). The applicant listed for this patent is KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.). Invention is credited to Hideto KATSUMA, Reiichi SUZUKI, Kenichi WATANABE.
Application Number | 20190358732 16/477714 |
Document ID | / |
Family ID | 63039674 |
Filed Date | 2019-11-28 |
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United States Patent
Application |
20190358732 |
Kind Code |
A1 |
WATANABE; Kenichi ; et
al. |
November 28, 2019 |
METHOD FOR JOINING DISSIMILAR MATERIALS, AND DISSIMILAR-MATERIAL
JOINED BODY
Abstract
A steel plate frame and a thin plate are made of different
materials. A plurality of through holes are formed in a portion of
the thin plate to be placed on the steel plate frame. A plurality
of projections 6c are formed on a support plate, each of the
projections being allowed to be inserted into a corresponding one
of the through holes. An adhesive is applied to a portion of the
steel plate frame on which the thin plate is placed. The thin plate
is placed on the steel plate frame, and the steel plate frame and
the thin plate are bonded together by the adhesive. The support
plate is placed on the thin plate to insert the projections into
the through holes. The projections and the steel plate frame are
welded to form a plurality of welded spots.
Inventors: |
WATANABE; Kenichi;
(Kobe-shi, Hyogo, JP) ; SUZUKI; Reiichi;
(Fujisawa-shi, Kanagawa, JP) ; KATSUMA; Hideto;
(Kobe-shi, Hyogo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.) |
Hyogo |
|
JP |
|
|
Assignee: |
KABUSHIKI KAISHA KOBE SEIKO SHO
(KOBE STEEL, LTD.)
Hyogo
JP
|
Family ID: |
63039674 |
Appl. No.: |
16/477714 |
Filed: |
January 10, 2018 |
PCT Filed: |
January 10, 2018 |
PCT NO: |
PCT/JP2018/000354 |
371 Date: |
July 12, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B23K 26/21 20151001;
B23K 11/20 20130101; B23K 26/348 20151001; B23K 2103/20 20180801;
B23K 37/04 20130101; B23K 26/22 20130101; B23K 11/11 20130101; B23K
9/16 20130101 |
International
Class: |
B23K 11/11 20060101
B23K011/11; B23K 26/22 20060101 B23K026/22; B23K 11/20 20060101
B23K011/20; B23K 37/04 20060101 B23K037/04 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 1, 2017 |
JP |
2017-016954 |
Claims
1. A method for joining dissimilar materials for joining an overlap
section between a first metal member and a second metal member
different in material from the first metal member, the method
comprising: forming a plurality of through holes in a portion of
the second metal member to be placed on the first metal member;
forming a plurality of projections on a support member, each of the
plurality of projections being allowed to be inserted into a
corresponding one of the through holes; applying a first adhesive
to a portion of the first metal member on which the second metal
member is placed or to a portion of the second metal member to be
placed on the first metal member; placing the second metal member
on the first metal member to bond the first metal member and the
second metal member together with the first adhesive; placing the
support member on the second metal member to insert the plurality
of projections into the through holes; and welding each of the
plurality of projections to the first metal member to form a
plurality of welded spots.
2. The method for joining dissimilar materials according to claim
1, further comprising: applying a second adhesive to the second
metal member or to the support member; and bonding the second metal
member and the support member together with the second
adhesive.
3. The method for joining dissimilar materials according to claim
1, wherein the first metal member is a long member whose cross
section orthogonal to a longitudinal direction has a U shape, a hat
shape, a rectangular shape, or a circular shape, the second metal
member is a plate-shaped member, and the support member is a long
strip-shaped member.
4. The method for joining dissimilar materials according to claim
3, wherein the first adhesive is applied to cause the first metal
member and the second metal member to be bonded together in a
section between the welded spots adjacent to each other.
5. The method for joining dissimilar materials according to claim
3, wherein the second metal member includes a first portion that is
placed on the first metal member, in which the plurality of through
holes are formed, and on which the support member is placed, and a
second portion that is not flush with the first portion and is
placed on a portion of the first metal member that is different
from a portion on which the first portion is placed, and the first
adhesive is applied to the portion of the first metal member on
which the second portion is placed or to a portion of the second
portion to be placed on the first metal member.
6. The method for joining dissimilar materials according to claim
5, wherein the first portion and the second portion each have a
flat-plate shape, and the first portion and the second portion are
connected to each other with a bent portion interposed between the
first portion and the second portion.
7. The method for joining dissimilar materials according to claim
5, wherein a cross section of the first metal member orthogonal to
the longitudinal direction has a circular shape, the first portion
of the second metal member has a curved-plate shape along a contour
of the first metal member, and the second portion of the second
metal member has a flat-plate shape.
8. The method for joining dissimilar materials according to claim
7, wherein a cross section of the support plate orthogonal to the
longitudinal direction has an arc shape along the first portion of
the second metal member.
9. The method for joining dissimilar materials according to claim
1, wherein the first metal member is made of steel, the second
metal member is made of aluminum or an aluminum alloy, and the
support member is made of steel.
10. The method for joining dissimilar materials according to claim
1, wherein the first metal member and the projections of the
support member are welded together by resistance spot welding,
laser welding, arc welding, or laser arc welding.
11. The method for joining dissimilar materials according to claim
1, wherein the projections of the support member are formed by deep
drawing, bulging, forging, or cutting.
12. A dissimilar-material joined body comprising: at least two
first metal members that are each a long member made of steel and
whose cross section orthogonal to a longitudinal direction has a U
shape, a hat shape, a rectangular shape, or a circular shape; a
second metal member that is a thin plate made of aluminum or an
aluminum alloy and is placed on each of the first metal members; a
support member that is made of steel and is placed on a portion of
the second metal member placed on each of the first metal members;
an adhesive layer that bonds the first metal member and the second
metal member together; and a plurality of welded spots where each
of a plurality of projections formed on the support member and
inserted into a corresponding one of a plurality of through holes
formed in the second metal member is welded to the first metal
member.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method for joining
dissimilar materials and a dissimilar-material joined body.
BACKGROUND ART
[0002] Patent Document 1 discloses a method for joining an aluminum
thin plate to a steel frame using a self-piercing rivet.
PRIOR ART DOCUMENT
Patent Document
[0003] Patent Document 1: JP 2002-174219 A
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0004] The method for joining dissimilar materials using the rivet
disclosed in Patent Document 1 cannot produce high joining
strength. Specifically, a steel frame and an aluminum thin plate
are joined together only with rivets, and thus, when a load is
applied to the thin plate, stress concentration occurs on the thin
plate around the rivets. This stress concentration may cause the
rivets to fracture or come off, and cause a portion of the thin
plate between riveted points adjacent to each other to fracture.
Further, an increase in the number of riveted points in order to
prevent the rivets from fracturing or coming off reduces a distance
between the riveted points adjacent to each other and accordingly
makes the thin plate susceptible to fracture.
[0005] An object of the present invention is to increase a joining
strength produced by a method for joining dissimilar materials and
of a dissimilar-material joined body.
Means for Solving the Problems
[0006] Provided according to a first aspect of the present
invention is a method for joining dissimilar materials for joining
an overlap section between a first metal member and a second metal
member different in material from the first metal member, the
method including forming a plurality of through holes in a portion
of the second metal member to be placed on the first metal member,
forming a plurality of projections on a support member, each of the
plurality of projections being allowed to be inserted into a
corresponding one of the through holes, applying a first adhesive
to a portion of the first metal member on which the second metal
member is placed or to a portion of the second metal member to be
placed on the first metal member, placing the second metal member
on the first metal member to bond the first metal member and the
second metal member together with the first adhesive, placing the
support member on the second metal member to insert the plurality
of projections into the through holes, and welding each of the
plurality of projections to the first metal member to form a
plurality of welded spots.
[0007] The second metal member is continuously or widely pressed
against the first metal member by the support member between the
welded spots adjacent to each other. This reduces stress
concentration around each of the welded spots.
[0008] Pressing the second metal member continuously or widely
against the first metal member with the support member between the
welded spots adjacent to each other prevents the second metal
member from undergoing out-of-plane deformation. Further, the
second metal member is bonded to the first metal member by a first
adhesive. These also reduce stress concentration around each of the
welded spots.
[0009] The above stress concentration reduction makes the second
metal member less susceptible to fracture from a portion joined to
the first metal member when a load is applied to the second metal
member and thus makes it possible to increase a joining strength
between the first metal member and the second metal member.
[0010] A second adhesive may be applied to the second metal member
or to the support member to bond the second metal member and the
support member together with the second adhesive.
[0011] Bonding the support member to the second metal member with
the second adhesive reduces stress concentration around each of the
welded spots more effectively and thus makes it possible to further
increase the joining strength between the first metal member and
the second metal member.
[0012] For example, the first metal member is a long member whose
cross section orthogonal to a longitudinal direction has a U shape,
a hat shape, a rectangular shape, or a circular shape, the second
metal member is a plate-shaped member, and the support member is a
long strip-shaped member.
[0013] The first adhesive bonds the first metal member and the
second metal member together between the welded spots adjacent to
each other.
[0014] Alternatively, the second metal member includes a first
portion that is placed on the first metal member, in which the
plurality of through holes are formed, and on which the support
member is placed, and a second portion that is not flush with the
first portion and is placed on a portion of the first metal member
that is different from a portion on which the first portion is
placed, and the first adhesive is applied to the portion of the
first metal member on which the second portion is placed or to a
portion of the second portion to be placed on the first metal
member.
[0015] The second metal member includes the first portion and the
second portion that is not flush with the first portion, and the
second portion of the second metal member in which no through hole
is formed is bonded to the first metal member with the first
adhesive. This allows a bonding surface constituted by the first
adhesive to be continuous to increase a bonding area, and thus
makes it possible to reduce stress concentration around each of the
welded spots more effectively and further increase the joining
strength between the first metal member and the second metal
member.
[0016] For example, the first portion and the second portion each
have a flat-plate shape, and the first portion and the second
portion are connected to each other with a bent portion interposed
between the first portion and the second portion.
[0017] Alternatively, a cross section of the first metal member
orthogonal to the longitudinal direction has a circular shape, the
first portion of the second metal member has a curved-plate shape
along a contour of the first metal member, and the second portion
of the second metal member has a flat-plate shape.
[0018] Since the first portion of the second metal member has a
curved-plate shape and extends along the contour of the first metal
member having a circular shape, it is possible to effectively
prevent moisture ingress into a gap between the first portion of
the second metal member and the first metal member. This in turn
makes it possible to prevent electrical contact between the first
metal member and the second metal member.
[0019] A cross section of the support plate orthogonal to the
longitudinal direction may have an arc shape along the first
portion of the second metal member.
[0020] This makes it possible to effectively prevent moisture
ingress into a gap between the support member and the first portion
of the second metal member. This in turn makes it possible to
prevent electrical contact between the support member and the
second metal member. Further, the support member has no sharp edge
projecting from the second portion of the second metal member, and
thus safety is increased.
[0021] For example, the first metal member is made of steel, the
second metal member is made of aluminum or an aluminum alloy, and
the support member is made of steel.
[0022] The first metal member and the projections of the support
member are welded together by resistance spot welding, laser
welding, arc welding, or laser arc welding.
[0023] The projections of the support member are formed by deep
drawing, bulging, forging, or cutting.
[0024] Provided according to a second aspect of the present
invention is a dissimilar-material joined body including at least
two first metal members that are each a long member made of steel
and whose cross section orthogonal to a longitudinal direction has
a U shape, a hat shape, a rectangular shape, or a circular shape, a
second metal member that is a thin plate made of aluminum or an
aluminum alloy and is placed on each of the first metal members, a
support member that is made of steel and is placed on a portion of
the second metal member placed on each of the first metal members,
an adhesive layer that bonds the first metal member and the second
metal member together, and a plurality of welded spots where each
of a plurality of projections formed on the support member and
inserted into a corresponding one of a plurality of through holes
formed in the second metal member is welded to the first metal
member.
Effects of the Invention
[0025] The method for joining dissimilar materials and the
dissimilar-material joined body according to the present invention
allow an increase in joining strength between the first metal
member and the second metal member made of different materials.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a schematic perspective view of a frame structure
manufactured by a method for joining dissimilar materials according
to a first embodiment;
[0027] FIG. 2 is a cross-sectional view taken along line II-II of
FIG. 1;
[0028] FIG. 3 is a cross-sectional view taken along line of FIG.
1;
[0029] FIG. 4 is an exploded perspective view of the frame
structure of FIG. 1;
[0030] FIG. 5 is a perspective view of a support plate;
[0031] FIG. 6 is a cross-sectional view taken along line VI-VI of
FIG. 5;
[0032] FIG. 7 is a cross-sectional view, similar to FIG. 6, of
another form of a projection;
[0033] FIG. 8 is a cross-sectional view for describing resistance
spot welding in the first embodiment;
[0034] FIG. 9 is a cross-sectional view for describing laser
welding in the first embodiment;
[0035] FIG. 10 is a cross-sectional view, similar to FIG. 2, of a
frame structure according to a first modification of the first
embodiment;
[0036] FIG. 11 is a cross-sectional view, similar to FIG. 3, of the
frame structure according to the first modification of the first
embodiment;
[0037] FIG. 12 is a cross-sectional view, similar to FIG. 2, of a
frame structure according to a second modification of the first
embodiment;
[0038] FIG. 13 is a cross-sectional view, similar to FIG. 3, of the
frame structure according to the second modification of the first
embodiment;
[0039] FIG. 14 is a cross-sectional view for describing resistance
spot welding in the second modification of the first
embodiment;
[0040] FIG. 15 is a cross-sectional view, similar to FIG. 2, of a
frame structure according to a third modification of the first
embodiment;
[0041] FIG. 16 is a cross-sectional view, similar to FIG. 3, of the
frame structure according to the third modification of the first
embodiment;
[0042] FIG. 17 is a cross-sectional view for describing resistance
spot welding in the third modification of the first embodiment;
[0043] FIG. 18 is a schematic perspective view of a frame structure
manufactured by a method for joining dissimilar materials according
to a second embodiment;
[0044] FIG. 19 is a cross-sectional view taken along line XIX-XIX
of FIG. 18;
[0045] FIG. 20 is a cross-sectional view taken along line XX-XX of
FIG. 18;
[0046] FIG. 21 is an exploded perspective view of the frame
structure of FIG. 18;
[0047] FIG. 22 is a cross-sectional view for describing resistance
spot welding in the second embodiment;
[0048] FIG. 23 is a cross-sectional view for describing laser
welding in the second embodiment;
[0049] FIG. 24 is a cross-sectional view, similar to FIG. 19, of a
frame structure according to a first modification of the second
embodiment;
[0050] FIG. 25 is a cross-sectional view, similar to FIG. 20, of
the frame structure according to the first modification of the
second embodiment;
[0051] FIG. 26 is a cross-sectional view, similar to FIG. 19, of a
frame structure according to a second modification of the second
embodiment;
[0052] FIG. 27 is a cross-sectional view, similar to FIG. 20, of
the frame structure according to the second modification of the
second embodiment;
[0053] FIG. 28 is an exploded perspective view of a frame structure
according to a third modification of the second embodiment;
[0054] FIG. 29 is a cross-sectional view, similar to FIG. 19, of
the frame structure according to the third modification of the
second embodiment;
[0055] FIG. 30 is a cross-sectional view, similar to FIG. 20, of
the frame structure according to the third modification of the
second embodiment;
[0056] FIG. 31 is a schematic perspective view of a frame structure
manufactured by a method for joining dissimilar materials according
to a third embodiment;
[0057] FIG. 32 is a cross-sectional view taken along line
XXXII-XXII of FIG. 31;
[0058] FIG. 33 is a cross-sectional view taken along line
XXXIII-XXXIII of FIG. 31;
[0059] FIG. 34 is an exploded perspective view of the frame
structure of FIG. 31;
[0060] FIG. 35 is a cross-sectional view for describing resistance
spot welding in the third embodiment;
[0061] FIG. 36 is a cross-sectional view for describing laser
welding in the third embodiment;
[0062] FIG. 37 is an exploded perspective view of a frame structure
according to a modification of the third embodiment;
[0063] FIG. 38 is a cross-sectional view, similar to FIG. 32, of
the frame structure according to the modification of the third
embodiment; and
[0064] FIG. 39 is a cross-sectional view, similar to FIG. 33, of
the frame structure according to the modification of the third
embodiment.
MODE FOR CARRYING OUT THE INVENTION
First Embodiment
[0065] FIGS. 1 to 4 show a frame structure (dissimilar-material
joined body) 1 manufactured by a method for joining dissimilar
materials according to a first embodiment of the present invention.
The application of this frame structure 1 is not limited to a
particular field, and the frame structure 1 is applicable to a
vehicle seat frame or a panel structure such as a floor.
[0066] The frame structure 1 includes a pair of steel frames (first
metal members) 2 that are long members made of steel such as high
tensile strength steel, and a thin plate (second metal member) 4
made of aluminum or an aluminum alloy. Both left and right ends of
the thin plate 4 in FIG. 1 are placed on and joined to the steel
frames 2. A support plate (support member) 6 that is a long
strip-shaped steel member is placed on each of the portions of the
thin plate 4 placed on the left and right steel frames 2. In the
present embodiment, a cross section of the support plate 6
orthogonal to a longitudinal direction has a slender rectangular
shape, and both surfaces 6a, 6b of the support plate 6 are flat. In
the drawings related to the present embodiment except FIG. 1 and
the drawings related to the second and third embodiments to be
described later, only a section where the thin plate 4 and the
right steel frame 2 are joined to each other in FIG. 1 is
illustrated.
[0067] Each of the steel frames 2 in the present embodiment has a U
shape in cross section orthogonal to the longitudinal direction,
and includes a top wall 2a and a pair of side walls 2b, 2c
extending downward in the drawings from both ends of the top wall
2a. The thin plate 4 is placed on the top wall 2a.
[0068] Referring to FIGS. 2 and 4, in a portion of the thin plate 4
that is placed on the top wall 2a of the steel frame 2, a plurality
of (in the present embodiment, five) through holes 4c penetrating
the thin plate 4 from a surface 4a on an upper side in the drawings
to a surface 4b on a lower side in the drawings are formed spaced
apart from one another. In the present embodiment, the plurality of
through holes 4c are arranged on a straight line extending in the
longitudinal direction of the steel frame 2. A shape of the through
holes 4c is circular in the present embodiment, but is not limited
to a particular shape as long as the through holes 4c can receive
projections 6c to be described later.
[0069] Referring to FIG. 5 together, on the support plate 6, a
plurality of (in the present embodiment, five) projections 6c
projecting from the surface 6a placed on the thin plate 4 are
formed spaced apart from one another in the longitudinal direction.
In the present embodiment, the projections 6c are arranged on a
straight line extending in the longitudinal direction of the steel
frame 2 as with the through holes 4c. As shown in FIG. 2, each of
the projections 6c is inserted into a corresponding one of the
through holes 4c. In other words, the numbers of and the spacing
between the through holes 4c and the projections 6c are set such
that each of the projections 6c aligns with a corresponding one of
the through holes 4c. A tip of each of the projections 6c is in
contact with an outer surface of the top wall 2a of the steel frame
2. A welded spot 7 is formed between the tip of the projection 6c
and the top wall 2a of the steel frame 2. In other words, the
support plate 6 is joined to the top wall 2a of the steel frame 2
by the welded spot 7 with the thin plate 4 sandwiched between the
support plate 6 and the top wall 2a of the steel frame 2.
[0070] In the present embodiment, one common support plate 6 is
provided for the five through holes 4c arranged in the longitudinal
direction of the steel frame 2. However, the support plate 6 may be
divided into two or more pieces.
[0071] Referring to FIGS. 3 and 4, a plurality of adhesive layers 8
are formed between the outer surface of the top wall 2a of the
steel frame 2 and the surface 4a of the thin plate 4 facing the top
wall 2a of the steel frame 2. The surface 4a of the thin plate 4
and the outer surface of the top wall 2a of the steel frame 2 are
bonded to each other by the adhesive layers 8 (first adhesive). As
shown in FIG. 4, in the present embodiment, one adhesive layer 8 is
disposed between the through holes 4c adjacent to each other. In
other words, one long and narrow adhesive layer 8 provided
continuously in the longitudinal direction of the steel frame 2 is
divided, at a position corresponding to each of the through holes
4c, into pieces, thereby forming the adhesive layers 8 in the
present embodiment.
[0072] Still referring to FIGS. 3 and 4, a plurality of adhesive
layers 9 are formed between the surface 4a on the upper side in the
drawings of the thin plate 4 and the surface 6a of the support
plate 6 from which the projections 6c project. The surface 6a of
the support plate 6 and the surface 4a of the thin plate 4 are
bonded to each other by the adhesive layers 9 (second adhesive). As
shown in FIG. 4, in the present embodiment, one adhesive layer 9 is
disposed between the through holes 4c adjacent to each other. In
other words, one long and narrow adhesive layer 9 provided
continuously in the longitudinal direction of the steel frame 2 is
divided, at a position corresponding to each of the through holes
4c, into pieces thereby forming the adhesive layers 9 in the
present embodiment.
[0073] The frame structure 1 of the present embodiment has the
following features.
[0074] The thin plate 4 is pressed, between the welded spots 7
adjacent to each other, continuously or widely against the steel
frame 2 by the support plate 6. This reduces stress concentration
around each of the welded spots 7.
[0075] Pressing the thin plate 4 continuously or widely against the
steel frame 2 with the support plate 6 between the welded spots 7
adjacent to each other prevents the thin plate 4 from undergoing
out-of-plane deformation. Further, the thin plate 4 is bonded to
the steel frame 2 by the adhesive layers 8. This also reduces the
stress concentration around the each of the welded spots 7.
[0076] The above stress concentration reduction makes the thin
plate 4 less susceptible to fracture from a portion joined to the
steel frame 2 when a load is applied to the thin plate 4 and thus
makes it possible to increase a joining strength between the steel
frame 2 and the thin plate 4. That is, although a weight of the
frame structure 1 is reduced by a combination of the steel frame 2
and the thin plate 4 made of aluminum or an aluminum alloy,
sufficient rigidity is secured.
[0077] In the present embodiment, bonding the support plate 6 to
the thin plate 4 with the adhesive layers 9 makes it possible to
more effectively reduce stress concentration around each of the
welded spots 7 and further increase the joining strength between
the steel plate frame 2 and the thin plate 4.
[0078] Next, a description will be given of a method for joining
dissimilar materials according to the present embodiment.
[0079] The through holes 4c are formed in the thin plate 4. The
through holes 4c can be formed by stamping. Specifically, with both
the surfaces 4a, 4b of the thin plate 4 sandwiched between a die
and a blank holder, forcing a punch through the thin plate 4
creates the through holes 4c.
[0080] The projections 6c are formed on the support plate 6. In the
present embodiment, the projections 6c are formed by deep drawing
or bulging. Accordingly, as shown in FIG. 6, a recess is formed at
a position corresponding to each of the projections 6c on the
surface 6b of the support plate 6 opposite to the surface 6a from
which the projections 6c project. Although deep drawing or bulging
is preferable in that the processing cost can be reduced, the
projections 6a may be formed by other methods such as forging or
cutting. When the projections 6a are formed by forging or cutting,
no recess is formed on the surface 6b of the support plate 6
opposite to the surface 6a from which the projections 6c project as
shown in FIG. 7.
[0081] External dimensions of the projections 6c need to be set so
as to allow the projections 6c to be inserted into the through
holes 4c of the thin plate 4. A dimension of each of the
projections 6 (a height of the projection 6) from the surface 6a of
the support plate 6 to the tip of the projection 6c needs to be set
such that the tip of the projection 6c comes into contact with the
outer surface of the top wall 2a when the support plate 6 is placed
on the thin plate 4 placed on the top wall 2a of the steel frame 2
to insert the projection 6c into a corresponding one of the through
holes 4c.
[0082] The process of forming the through holes 4c in the thin
plate 4 and the process of forming the projections 6c on the
support plate 6 may be performed sequentially in that order or
reverse order. Further, the two processes may be performed
simultaneously or in parallel.
[0083] Next, an adhesive (first adhesive) is applied to a portion
of the outer surface of the top wall 2a of the steel frame 2 on
which the thin plate 4 is placed to form the adhesive layers 8.
Examples of the adhesive used for the adhesive layers 8 include an
epoxy-based adhesive, a urethane-based adhesive, and an
acrylic-based adhesive. The adhesive may be applied to a portion of
the surface 4b on the lower side in the drawings of the thin plate
4 to be placed on the outer surface of the top wall 2a of the steel
frame 2 to form the adhesive layers 8.
[0084] After the adhesive layers 8 are formed, the surface 4b on
the lower side in the drawings of the thin plate 4 is placed on the
outer surface of the top wall 2a of the steel frame 2, and the
steel frame 2 and the thin plate 4 are bonded to each other by the
adhesive layers 8.
[0085] Next, an adhesive (second adhesive) is applied to the
surface 6a of the support plate 6 from which the projections 6c
project to form the adhesive layers 9. Examples of the adhesive
used for the adhesive layers 9 include an epoxy-based adhesive, a
urethane-based adhesive, and an acrylic-based adhesive. The
adhesive may be applied to a portion of the surface 4a on the upper
side in the drawings of the thin plate 4 on which the support plate
6 is placed to form the adhesive layers 9.
[0086] After the adhesive layers 9 are formed, the surface 6a of
the support plate 6 is placed on the surface 4a on the upper side
in the drawings of the thin plate 4, and the thin plate 4 and the
support plate 6 are bonded to each other by the adhesive layers 9.
When the support plate 6 is placed on the thin plate 4, each of the
projections 6 of the support plate 6 is inserted into a
corresponding one of the through holes 4c of the thin plate 4.
[0087] Next, the projections 6a of the support plate 6 are welded
to the top wall 2a of the steel frame 2. Examples of this welding
include resistance spot welding, laser welding, arc welding, and
laser arc welding. As conceptually shown in FIG. 8, for the
resistance spot welding, a portion, corresponding to the projection
6a, of the support plate 6 and a portion, opposite to the
projection 6a, of the top wall 2a of the steel frame 2 are
sandwiched between electrodes 100, 101. An electric current is
applied under pressure applied by the electrodes 100, 101 to cause
an energized section to be partially melted by heat generated due
to contact resistance and then solidified to become the welded spot
7. As conceptually shown in FIG. 9, for the laser welding, a laser
beam 103 emitted from a light source 102 causes an irradiated
section to be partially melted and then solidified to become the
welded spot 7.
[0088] Through the above processes, the frame structure 1 shown in
FIG. 1 is manufactured.
[0089] FIGS. 10 to 17 show various modifications of the first
embodiment.
[0090] In a first modification shown in FIGS. 10 and 11, the cross
section of the steel plate frame 2 orthogonal to the longitudinal
direction has a hat shape. That is, in addition to the top wall 2a
and the side walls 2b, 2c, the steel plate frame 2 includes flanges
2d, 2e extending in a lateral direction from lower ends in the
drawings of the side walls 2b, 2c, respectively.
[0091] In a second modification shown in FIGS. 12 and 13, instead
of the steel plate frame 2, the thin plate 4 is joined to a steel
pipe 3 (rectangular steel pipe) whose cross section orthogonal to
the longitudinal direction has a rectangular shape. The steel pipe
3 includes a top wall 3a, side walls 3b, 3c extending downward in
the drawings from both ends of the top wall 3a, and a bottom wall
3d connecting ends on lower sides in the drawings of the side walls
3b, 3c. The welded spot 7 is formed between each of the projections
6c of the support plate 6 and the top wall 3a of the steel pipe 3.
Further, the surface 4b on the lower side in the drawings of the
thin plate 4 and the top wall 3a of the steel pipe 3 are bonded to
each other by the adhesive layers 8. As conceptually shown in FIG.
14, in a case where the welded spot 7 is formed by the spot
resistance welding, one electrode 100 is disposed at a position on
the surface 6b of a reinforcing plate 6 corresponding to the
projection 6c, and the other electrode 101 is disposed at a
position on the bottom wall 3d of the steel pipe 3 opposite to the
projection 6c.
[0092] In a third modification shown in FIGS. 15 and 16, instead of
the steel plate frame 2, the thin plate 4 is joined to a steel pipe
3 (circular steel pipe) whose cross section orthogonal to the
longitudinal direction has a circular shape. The welded spot 7 is
formed between each of the projections 6c of the support plate 6
and a portion of an outer peripheral surface of the steel pipe 3.
Further, the surface 4b on the lower side in the drawings of the
thin plate 4 and the portion of the outer peripheral surface of the
steel pipe 3 are bonded to each other by the adhesive layers 8. As
conceptually shown in FIG. 17, in a case where the welded spot 7 is
formed by the spot resistance welding, one electrode 100 is
disposed at a position on the surface 6b of the reinforcing plate 6
corresponding to the projection 6c, and the other electrode 101 is
disposed at a position on the outer peripheral surface of the steel
pipe 3 opposite to the projection 6c.
[0093] The second and third embodiments of the present invention
will now be described. In the drawings related to these
embodiments, the same or the same components as in the first
embodiment are denoted by the same symbols. Further, a frame
structure 1 and a method for joining dissimilar materials for
manufacturing the frame structure 1 in these embodiments are the
same as in the first embodiment in points of which no particular
description is given.
Second Embodiment
[0094] FIGS. 18 to 21 show a frame structure 1 manufactured by a
method for joining dissimilar materials according to the second
embodiment of the present invention.
[0095] In the present embodiment, a thin plate 5 made of aluminum
or an aluminum alloy is joined to a steel pipe 3 (rectangular steel
pipe) whose cross section orthogonal to the longitudinal direction
has a rectangular shape. The steel pipe 3 includes a top wall 3a,
side walls 3b, 3c, and a bottom wall 3d.
[0096] The thin plate 4 in the first embodiment is simply flat
(see, for example, FIG. 1). On the other hand, the thin plate 5 in
the present embodiment is formed of a flat thin plate whose end is
bent. Specifically, the thin plate 5 includes a main body 5a
(second portion) having a flat-plate shape and an end 5b that has a
flat-strip shape and is connected to the main body 5a with a bent
portion 5c interposed between the main body 5a and the end 5b. A
virtual plane including the main body 5a is different from a
virtual plane including the end 5b. That is, the main body 5a and
the end 5b extend on different virtual planes. In other words, the
main body 5a and the end 5b are formed so as not to be flush with
each other.
[0097] A portion of the main body 5a of the thin plate 5 adjacent
to the bent portion 5c is placed on the outer surface of the top
wall 3a of the steel pipe 3. Further, the end 5b of the thin plate
5 is placed on the outer surface of the side wall 3b of the steel
pipe 3. Furthermore, a support plate 6 is placed on a surface 5f on
an outer side of the end 5b of the thin plate 5.
[0098] In the end 5b of the thin plate 5, a plurality of (in the
present embodiment, five) through holes 5h penetrating the end 5b
from one surface 5f to the other surface 5g are formed spaced apart
from one another. These through holes 5h are arranged on a straight
line extending in the longitudinal direction of the steel pipe 3.
No through hole penetrating the main body 5a from a surface 5d to a
surface 5e is formed in the main body 5a of the thin plate 5.
[0099] On the support plate 6, a plurality of (in the present
embodiment, five) projections 6c projecting from a surface 6a
placed on the end 5 of the thin plate 5 are formed spaced apart
from each other in the longitudinal direction. Each of the
projections 6c is inserted into a corresponding one of the through
holes 5h to bring the tip of the projection 6c into contact with
the outer surface of the side wall 3b of the steel pipe 3. A welded
spot 7 is formed between the tip of each of the projections 6c and
the side wall 3b of the steel pipe 3. In other words, the support
plate 6 is joined to the side wall 3b of the steel pipe 3 by the
welded spots 7 with the end 5b of the thin plate 5 sandwiched
between the support plate 6 and the side wall 3b of the steel pipe
3.
[0100] Referring to FIGS. 19 to 21, an adhesive layer 8 is formed
between the outer surface of the top wall 3a of the steel pipe 3
and a surface 5e on the lower side in the drawings of the main body
5b of the thin plate 5. The surface 5e of the main body 5b of the
thin plate 5 and the outer surface of the top wall 3a of the steel
pipe 3 are bonded to each other by the adhesive layer 8 (first
adhesive). Referring to FIG. 21, since no through hole is formed in
the main body 5a of the thin plate 5 as described above, the
adhesive layer 8 is not divided, but formed continuously in the
longitudinal direction of the steel pipe 3.
[0101] The frame structure 1 of the present embodiment has the
following features.
[0102] The end 5b of the thin plate 5 is pressed, between the
welded spots 7 adjacent to each other, continuously or widely
against the steel pipe 3 by the support plate 6. This reduces
stress concentration around each of the welded spots 7.
[0103] Pressing the end 5b continuously or widely against the steel
pipe 3 with the support plate 6 between the welded spots 7 adjacent
to each other prevents the thin plate 5 from undergoing
out-of-plane deformation. Further, the main body 5a of the thin
plate 5 is bonded to the steel pipe 3 by the adhesive layer 8. This
also reduces the stress concentration around the each of the welded
spots 7.
[0104] The above stress concentration reduction makes the thin
plate 5 less susceptible to fracture from a portion joined to the
steel frame 2 when a load is applied to the thin plate 5 and thus
makes it possible to increase a joining strength between the steel
pipe 3 and the thin plate 5. That is, although a weight of the
frame structure 1 is reduced by a combination of the steel pipe 3
and the thin plate 5 made of aluminum or an aluminum alloy,
sufficient rigidity is secured.
[0105] The thin plate 5 includes the end 5b, and the main body 5a
that is not flush with the end 5b, and the main body 5a having no
through hole is bonded to the steel pipe 3 by the adhesive layer 8.
This allows a bonding surface constituted by the adhesive layer 8
to be continuous to increase a bonding area, and thus makes it
possible to reduce stress concentration around each of the welded
spots 7 more effectively and further increase the joining strength
between the steel pipe 3 and the thin plate 5.
[0106] As in the first embodiment, an adhesive layer (see, for
example, symbol 9 in FIG. 3) may be formed between the surface 5f
on the outer side of the end 5b of the thin plate 5 and the surface
6a of the reinforcing plate 6 where the projections 6c are formed.
Bonding the support plate 6 to the end 5b of the thin plate 5 with
this adhesive makes it possible to reduce stress concentration
around each of the welded spots 7 more effectively and further
increase the joining strength between the steel plate frame 2 and
the thin plate 4.
[0107] Next, a description will be given of a method for joining
dissimilar materials according to the present embodiment.
[0108] The through holes 5h are formed, by a process such as
stamping, in a portion, corresponding to the end 5b, of the thin
plate 5 that is entirely flat before the bent portion 5c is formed.
After the through holes 5h are formed, the thin plate 5 is bent to
have the main body 5a, the bent portion 5c, and the end 5b.
[0109] The projections 6c are formed on the support plate 6. As
described in relation to the first embodiment, the projections 6c
may be formed by deep drawing or bulging, or by a different process
such as forging or cutting.
[0110] The process of machining the thin plate 5 and the process of
forming the projections 6c on the support plate 6 may be performed
sequentially in that order or reverse order. Further, the two
processes may be performed simultaneously or in parallel.
[0111] Next, the adhesive (first adhesive) is applied to the outer
surface of the top wall 3a of the steel pipe 3 to form the adhesive
layer 8. The adhesive may be applied to a portion of the surface 5e
on the lower side in the drawings of the main body 5a of thin plate
5 to be placed on the outer surface of the top wall 3a of the steel
pipe 3 to form the adhesive layer 8.
[0112] After the adhesive layer 8 is formed, the thin plate 5 is
placed on the steel pipe 3. Specifically, a portion of the main
body 5a of the thin plate 5 adjacent to the bent portion 5c is
placed on the outer surface of the top wall 3a of the steel pipe 3,
and the steel pipe 3 and the main body 5a of the thin plate 5 are
bonded to each other by the adhesive layer 8. Further, the end 5b
of the thin plate 5 is placed on the side wall 3b of the steel pipe
3.
[0113] Next, the surface 6a of the support plate 6 is placed on the
surface 5f on the outer side of the end 5b of the thin plate 5
placed on the side wall 3a of the steel pipe 3. At this time, each
of the projections 6 of the support plate 6 is inserted into a
corresponding one of the through holes 5h of the end 5b of the thin
plate 5.
[0114] Subsequently, the projections 6a of the support plate 6 are
welded to the side wall 3b of the steel pipe 3. Examples of this
welding include resistance spot welding (see FIG. 22), laser
welding (see FIG. 23), arc welding, and laser arc welding.
Referring to FIG. 22, for the resistance spot welding, a portion,
corresponding the projection 6a, of the support plate 6 and a
portion, opposite to the projection 6a, of the bottom wall 3d of
the steel pipe 3 are sandwiched between electrodes 100, 101.
[0115] Through the above processes, the frame structure 1 shown in
FIG. 18 is manufactured.
[0116] FIGS. 24 to 30 show modifications of the second
embodiment.
[0117] In a first modification shown in FIGS. 24 and 25, the thin
plate 5 is joined to a steel plate frame 2 having a U shape. The
main body 5a of the thin plate 5 is placed on a top wall 2a of the
steel plate frame 2 and bonded to the top wall 2a by the adhesive
layer 8. The end 5b of the thin plate 5 is placed on a side wall 2b
of the steel plate frame 5. Forming the welded spot 7 between each
of the projections 6a of the support plate 6 placed on the end 5b
of the thin plate 5 and the side wall 2b of the steel plate frame 5
causes the end 5b of the thin plate 5 to be held between the side
wall 2b of the steel plate frame 5 and the support plate 6.
[0118] In a second modification shown in FIG. 26 and FIG. 27, the
thin plate 5 is joined to a steel plate frame 2 having a hat shape.
This modification is the same as the first modification (FIGS. 24
and 25) except the cross-sectional shape of the frame steel plate
2.
[0119] In a third modification shown in FIGS. 28 to 30, the thin
plate 5 is joined to a steel pipe 3 having a circular shape. The
main body 5a of the thin plate 5 is placed on a portion of the
steel pipe 3 and bonded to the steel pipe 3 by the adhesive layer
8. The end 5b of the thin plate 5 is placed on a portion of the
steel pipe 3 that is different from the portion where the adhesive
layer 8 is formed. Forming the welded spot 7 between each of the
projections 6a of the support plate 6 placed on the end 5b of the
thin plate 5 and the steel pipe 3 causes the end 5b of the thin
plate 5 to be held between the steel pipe 3 and the support plate
6.
Third Embodiment
[0120] FIGS. 31 to 34 show a frame structure 1 manufactured by a
method for joining dissimilar materials according to the second
embodiment of the present invention.
[0121] In the present embodiment, a thin plate 5 made of aluminum
or an aluminum alloy is joined to a steel pipe 3 (circular steel
pipe) whose cross section orthogonal to the longitudinal direction
has a circular shape.
[0122] The thin plate 5 in the present embodiment is formed of a
flat thin plate whose end is curved. Specifically, the thin plate 5
includes a main body 5a (second portion) having a flat-plate shape
and an end 5b (first portion) that has a curved-plate shape and is
connected to the main body 5a. As in the second embodiment, in
other words, the main body 5a and the end 5b are formed so as not
to be flush with each other. The end 5 is formed such that at least
a surface 5g on an inner side is a curved surface having a
curvature along a contour of the steel pipe 3.
[0123] A portion of the main body 5a of the thin plate 5 adjacent
to the end 5b having a curved shape is placed on a portion on an
upper side in the drawings of an outer surface of the steel pipe 3.
The end 5b of the thin plate 5 is further placed on a portion on a
right side in the drawings of the outer surface of the steel pipe
3. Furthermore, a support plate 6 is placed on a surface 5f on an
outer side of the end 5b of the thin plate 5.
[0124] The support plate 6 in the present embodiment does not have
a simple flat-strip shape. Specifically, the support plate 6 is
formed such that a cross section orthogonal to the longitudinal
direction of at least a surface 6a on which projections 6a are
formed has an arc shape having a curvature along the end 5b of the
thin plate 5.
[0125] Each of the projections 6c of the support plate 6 is
inserted into a corresponding one of through holes 5h of the end 5b
of the thin plate 5 to bring the tip of the projection 6c into
contact with the outer surface of the steel pipe 3. A welded spot 7
is formed between the tip of each of the projections 6c and the
outer surface of the steel pipe 3. In other words, the support
plate 6 is joined to a side wall 3b of the steel pipe 3 by the
welded spots 7 with the end 5b of the thin plate 5 sandwiched
between the support plate 6 and the steel pipe 3. Further, the
outer surface of the steel pipe 3 and a surface 5e on the lower
side in the drawings of the main body 5b of the thin plate 5 are
bonded to each other by an adhesive layer 8.
[0126] The frame structure 1 of the present embodiment has the
following features in addition to the features of the second
embodiment.
[0127] Since the end 5b of the thin plate 5 has a curved-plate
shape and extends along the contour of the steel pipe 3 having a
circular shape, it is possible to effectively prevent moisture
ingress into a gap between the end 5b of the thin plate 5 and the
steel pipe 3. This in turn makes it possible to prevent electrical
contact between the steel pipe 3 and the thin plate 5.
[0128] Since the cross section of the support plate 6 orthogonal to
the longitudinal direction has an arc shape along the end 5b of the
thin plate 5, it is possible to effectively prevent moisture
ingress into a gap between the support plate 6 and the end 5b of
the thin plate 5. This in turn makes it possible to prevent
electrical contact between the support plate 6 and the thin plate
5. Further, the support plate 6 has no sharp edge projecting from
the end 5b of the thin plate 5, and thus safety is increased.
[0129] As in the first embodiment, an adhesive layer (see, for
example, symbol 9 in FIG. 3) may be formed between the surface 5f
on the outer side of the end 5b of the thin plate 5 and the surface
6a of the reinforcing plate 6 where the projections 6c are formed.
Bonding the support plate 6 to the end 5b of the thin plate 5 with
this adhesive makes it possible to reduce stress concentration
around each of the welded spots 7 more effectively and further
increase the joining strength between the steel plate frame 2 and
the thin plate 4.
[0130] The method for joining dissimilar materials according to the
present embodiment is the same as in the second embodiment except
that the end 5b having a curved shape is formed in the thin plate 5
rather than the formation of the bent portion 5c and the end 5b
having a flat shape (see, for example, FIG. 21), and that the
support plate 6 is machined to have an arc-shaped cross section.
Examples of the welding of the projections 6c of the support plate
6 to the steel pipe 3 include resistance spot welding (see FIG.
35), laser welding (see FIG. 36), arc welding, and laser arc
welding as in the second embodiment.
[0131] In FIGS. 37 to 39, in a modification of the third
embodiment, the cross section of the support plate 6 orthogonal to
the longitudinal direction does not have an arc shape. That is, for
example, as in the first embodiment, the cross section of the
support plate 6 orthogonal to the longitudinal direction in this
modification has a slender rectangular shape.
[0132] The present invention has been described with reference to
an example where a thin plate made of aluminum or an aluminum alloy
is joined to a steel frame or steel pipe. The present invention is,
however, applicable to joining of dissimilar materials other than
the combination of steel and aluminum or an aluminum alloy.
DESCRIPTION OF SYMBOLS
[0133] 1: Frame structure (dissimilar-material joined body), 2:
Steel frame (first metal member), 2a: Top wall, 2b; 2c: Side wall,
2d; 2e: Flange, 3: Steel pipe (first metal member), 3a: Top wall,
3b; 3c: Side wall, 3d: Bottom wall, 4: Thin plate, 4a; 4b: Surface,
4c: Through hole, 5: Thin plate, 5a: Main body (second portion),
5d; 5e: Surface, 5b: End (first portion), 5f; 5g: Surface 5h:
Through hole, 5c: Bent portion, 6: Support plate (support member),
6a; 6b: Surface, 6c: Projection, 7: Welded spot, 8; 9: Adhesive
layer, 100; 101: Electrode, 102: Light source, 103: Laser beam
* * * * *